***Update*** Judging from pregame formations, it appears Joe Looney will start at right guard. That means the starting offensive line will have the same five that started every preseason game -- Looney at right guard and Jonathan Martin at right tackle.

It also means that Alex Boone will be the main backup at guard and tackle and undrafted rookie Dillon Farrell will be in reserve. Farrell can play all five o-line spots.

ARLINGTON, Texas -- Neither of the 49ers' standout defensive linemen in the preseason, Quinton Dial and Tank Carradine, will suit up for today's game in Dallas. Both were among the seven inactives. Carradine was not in uniform at all last season; Dial was only active for three games.

Ray McDonald, meanwhile, figures to start at left defensive end. The only lineup change announced by the 49ers was that Jonathan Martin would start at right tackle for injured Anthony Davis (hamstring). Left ambiguous is whether Alex Boone or Joe Looney will start at right guard.

Receiver Michael Crabtree is dealing with a calf injury but is active and looks as if he will play. He missed Wednesday’s practice but was on hand for Thursday’s and Friday’s sessions. Quinton Patton is the only wide receiver who is not active. That means both Brandon Lloyd and Bruce Ellington are in uniform.

49ers inactives

QB Josh Johnson

WR Quinton Patton

CB Chris Cook

C Marcus Martin

T Anthony Davis

DL Quinton Dial

DL Tank Carradine

Meanwhile, practice-squad player Lawrence Okoye warmed up with the reserve offensive linemen before the game. Practice squad players often are asked to play multiple positions in the run-up to a game. Defensive backs, for example, sometimes line up as the opponent's receivers.

With Okoye, however, the team is still searching for his most natural spot. He played defensive end the last two seasons and will continue to do so, general manager Trent Baalke said. But the 49ers also want to see how he performs as an offensive tackle.

After all, he seems to have the right body type and athleticism for the offensive line. He's 6-5, 305 pounds with long arms and long legs. And his mental makeup may skew more to being an offensive lineman than it does the more instinctive defensive line.

Read Matt Barrows’ blogs and archives at www.sacbee.com/sf49ers.